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|
#!perl -w
use strict;
use warnings;
use Qpsmtpd::Constants;
use Qpsmtpd::DSN;
use Qpsmtpd::TcpServer;
#use ParaDNS; # moved into register
use Socket;
my %invalid = ();
my $has_ipv6 = Qpsmtpd::TcpServer::has_ipv6();
sub register {
my ($self, $qp) = @_;
foreach my $i ($self->qp->config("invalid_resolvable_fromhost")) {
$i =~ s/^\s*//;
$i =~ s/\s*$//;
if ($i =~ m#^((\d{1,3}\.){3}\d{1,3})/(\d\d?)#) {
$invalid{$1} = $3;
}
}
eval 'use ParaDNS';
if ($@) {
warn "could not load ParaDNS, plugin disabled";
return DECLINED;
}
$self->register_hook(mail => 'hook_mail_start');
$self->register_hook(mail => 'hook_mail_done');
}
sub hook_mail_start {
my ($self, $transaction, $sender) = @_;
return DECLINED
if ($self->connection->notes('whitelisthost'));
if ($sender ne '<>') {
unless ($sender->host) {
# default of addr_bad_from_system is DENY, we use DENYSOFT here to
# get the same behaviour as without Qpsmtpd::DSN...
return
Qpsmtpd::DSN->addr_bad_from_system(DENYSOFT,
"FQDN required in the envelope sender");
}
return DECLINED if $sender->host =~ m/^\[(\d{1,3}\.){3}\d{1,3}\]$/;
unless ($self->check_dns($sender->host)) {
return Qpsmtpd::DSN->temp_resolver_failed(
"Could not resolve " . $sender->host);
}
return YIELD;
}
return DECLINED;
}
sub hook_mail_done {
my ($self, $transaction, $sender) = @_;
return DECLINED
if ($self->connection->notes('whitelisthost'));
if ($sender ne "<>" && !$transaction->notes('resolvable_fromhost')) {
# default of temp_resolver_failed is DENYSOFT
return Qpsmtpd::DSN->temp_resolver_failed(
"Could not resolve " . $sender->host);
}
return DECLINED;
}
sub check_dns {
my ($self, $host) = @_;
my @host_answers;
my $qp = $self->qp;
$qp->input_sock->pause_read;
my $a_records = [];
my $num_queries = 1; # queries in progress
my $mx_found = 0;
ParaDNS->new(
callback => sub {
my $mx = shift;
return if $mx =~ /^[A-Z]+$/; # error
my $addr = $mx->[0];
$mx_found = 1;
$num_queries++;
ParaDNS->new(
callback => sub {
push @$a_records, $_[0] if $_[0] !~ /^[A-Z]+$/;
},
finished => sub {
$num_queries--;
$self->finish_up($qp, $a_records, $num_queries);
},
host => $addr,
type => 'A',
);
if ($has_ipv6) {
$num_queries++;
ParaDNS->new(
callback => sub {
push @$a_records, $_[0] if $_[0] !~ /^[A-Z]+$/;
},
finished => sub {
$num_queries--;
$self->finish_up($qp, $a_records, $num_queries);
},
host => $addr,
type => 'AAAA',
);
}
},
finished => sub {
unless ($mx_found) {
$num_queries++;
ParaDNS->new(
callback => sub {
push @$a_records, $_[0] if $_[0] !~ /^[A-Z]+$/;
},
finished => sub {
$num_queries--;
$self->finish_up($qp, $a_records, $num_queries);
},
host => $host,
type => 'A',
);
if ($has_ipv6) {
$num_queries++;
ParaDNS->new(
callback => sub {
push @$a_records, $_[0] if $_[0] !~ /^[A-Z]+$/;
},
finished => sub {
$num_queries--;
$self->finish_up($qp, $a_records, $num_queries);
},
host => $host,
type => 'AAAA',
);
}
}
$num_queries--;
$self->finish_up($qp, $a_records, $num_queries);
},
host => $host,
type => 'MX',
)
or $qp->input_sock->continue_read, return;
return 1;
}
sub finish_up {
my ($self, $qp, $a_records, $num_queries) = @_;
return if defined $qp->transaction->notes('resolvable_fromhost');
foreach my $addr (@$a_records) {
if (is_valid($addr)) {
$qp->transaction->notes('resolvable_fromhost', 1);
$qp->input_sock->continue_read;
$qp->run_continuation;
return;
}
}
unless ($num_queries) {
# all queries returned no valid response
$qp->transaction->notes('resolvable_fromhost', 0);
$qp->input_sock->continue_read;
$qp->run_continuation;
}
}
sub is_valid {
my $ip = shift;
my ($net, $mask);
foreach $net (keys %invalid) {
$mask = $invalid{$net};
$mask = pack "B32", "1" x ($mask) . "0" x (32 - $mask);
return 0
if join(".", unpack("C4", inet_aton($ip) & $mask)) eq $net;
}
return 1;
}
|
